Munmun Ghosh

KOtBu mediated efficient approach for the synthesis of fused heterocycles via intramolecular O-/N-arylations

A novel and efficient methodology for the synthesis of 6H-benzo[c]chromenes, 6H-benzo[c]chromen-6-ones, carbazoles, dibenzofurans, dibenzooxepins has been developed. The reaction goes through intramolecular O-/N-arylations with sp2C–Br bonds via typical SNAr pathway in presence of potassium-tert-butoxide base.

Pd-free Sonogashira coupling: one pot synthesis of phthalide via domino Sonogashira coupling and 5-exo-dig cyclization

Phthalides have been synthesized exclusively in one pot via Pd-free Sonogashira coupling. A Cu-catalyzed domino Sonogashira coupling and 5-exo-dig cyclization between suitable substituted ortho-bromobenzoic acids and terminal alkynes afforded phthalides in good yields under mild reaction conditions.

Copper catalyzed room temperature lactonization of aromatic C–H bond: a novel and efficient approach for the synthesis of dibenzopyranones

We have developed a novel and efficient methodology for the intramolecular aryl C–H oxidative lactonization of 2-arylbenzaldehyde using a low-cost CuCl catalyst and TBHP as the oxidant at room temperature. We applied the methodology to the synthesis of a series of dibenzopyranones.

Synthesis of α, β and γ-carbolines via Pd-mediated Csp2-H/N–H activation

An efficient method for the synthesis of halo-carbolines has been developed via Pd-catalysed formation of C–N bonds through Csp2-H/N–H activation of 4-methyl-N-[2-(pyridine-3-yl)phenyl] benzenesulfonamide derivatives. Pd(OAc)2 in the presence of Cu(OAc)2 as oxidant afforded halo-carbolines in good to excellent yields with tolerance to a variety of substituents.

Synthesis of 4,5,6-trisubstituted-1,3-dihydroisobenzofurans by virtue of palladium-catalyzed domino carbopalladation of bromoenynes and internal alkynes

An efficient hetero-annulation protocol has been developed for the construction of 4,5,6-trisubstituted-1,3-dihydroisobenzofurans via palladium-catalyzed domino carbopalladation of bromoenynes and internal alkynes. The reaction followed domino intramolecular Heck cyclization (5-exo-dig) and termination of the resulting diene with an internal alkyne to give highly substituted isobenzofurans in moderate to good yields.

P4S10 and Na2S-mediated novel annulation routes to c-fused thiophenes

Two efficient hetero-annulation protocols have been developed for the synthesis of stable substituted c-fused thiophene derivatives with moderate to high yield. 3-(2-formyl-phenyl)-acrylic acid esters afforded benzo[c]thiophenes in the presence of phosphorus pentasulfide in refluxing benzene while 3-(2-formyl-cycloalkenyl)α,β-unsaturated esters resulted in the formation of c-fused thiophene derivatives when reacted with sodium sulfide in refluxing tetrahydrofuran.

Synthesis of bis-exocyclic conjugated diene containing 1,2,3,4-tetrahydroquinoline derivatives via palladium-catalyzed intramolecular Heck cyclization

An efficient method has been developed for the synthesis of bis-exocyclic conjugated diene containing 1,2,3,4-tetrahydroquinoline derivatives via palladium-catalyzed intramolecular Heck cyclization of (2-bromo-allyl)-(2-phenylethynyl-phenyl)-amines. The reaction followed 6-exo-dig cyclization to yield the desired products in moderate to good yields.

A Review on Quantum Dots: Synthesis to In- silico Analysis as Next Generation Antibacterial Agents

Succumbing to Multi-Drug Resistant (MDR) bacteria is a great distress to the recent health care system. Out of the several attempts that have been made to kill MDR pathogens, a few gained short-lived success. The failures, of the discovered or innovated antimicrobials, were mostly due to their high level of toxicity to hosts and the phenomenal rate of developing resistance by the pathogens against the new arsenal. Recently, a few quantum dots were tested against the pathogenic bacteria and therefore, justified for potential stockpiling of next-generation antibacterial agents. The key players for antimicrobial properties of quantum dots are considered to be Reactive Oxygen Species (ROS). The mechanism of reaction between bacteria and quantum dots needs to be better understood. They are generally targeted towards the cell wall and membrane components as lipoteichoic acid and phosphatidyl glycerol of bacteria have been documented here. In this paper, we have attempted to simulate ZnS quantum dots and have analysed their mechanism of reaction as well as binding potential to the above bacterial membrane components using CDOCKER. Results have shown a high level of antibacterial activity towards several pathogenic bacteria which specify their potentiality for future generation antibacterial drug development.

Synthesis of 1,3-dibromo-2-aryl-1H-indenes via NBS mediated unusual bromination of 2-alkynylbenzaldoximes

We have investigated a very interesting side-pathway leading to 1,3-dibromo-2-aryl-1H-indenes as opposed to isoquinoline N-oxides during the NBS mediated synthesis of isoquinoline N-oxide from 2-alkynylbenzaldoximes.